Gate driver ASIC for an automotive starter/alternator

ABSTRACT

A starter/alternator system for an engine and a battery of an automobile are provided. The system includes a starter/alternator machine; a three phase MOSgate control inverter/bridge electrically coupled to the starter/alternator machine, the three phase MOSgate control inverter/bridge including bridge connected MOSgated devices; a control ASIC electrically coupled to the bridge connected MOSgated devices of the three phase MOSgate control inverter/bridge, the control ASIC including all control circuitry required to control the starter/alternator machine; and a motor drive circuit electrically coupled to the control ASIC.

RELATED APPLICATIONS

[0001] This application is based on and claims the benefit of U.S.Provisional Application No. 60/433,472 filed on Dec. 13, 2002, entitledGATE DRIVER ASIC FOR AN AUTOMOTIVE STARTER/ALTERNATOR, the entirecontents of which are expressly incorporated herein by reference.

FIELD OF THE INVENTION

[0002] This invention relates to automotive starter alternators and morespecifically relates to a novel application specific integrated circuit(ASIC) for a starter/alternator.

BACKGROUND OF THE INVENTION

[0003] Automotive starter alternators are well known and employ a powersupply which contains a three phase bridge made of MOSgated devices suchas power MOSFETs and/or IGBTs. The gates of these MOSGATED devices aresuitably controlled by various control circuits, under the influence ofa motor drive controller. Until now, the controls for the MOSgateddevices have included numerous segregated circuit assemblies, many ofwhich are implemented on separate Printed Circuit Boards (PCBs) inseparate wire harnesses.

BRIEF DESCRIPTION OF THE INVENTION

[0004] It is an object of the present invention to overcome thedisadvantages of the prior art by providing a starter/alternator systemfor an engine and a battery of an automobile, which employs a novelcontrol ASIC including all control “intelligence” (i.e., controlcircuitry) required to control a starter/alternator machine. Morespecifically, the system includes a starter/alternator machine; a threephase MOSgate control inverter/bridge electrically coupled to thestarter/alternator machine, the three phase MOSgate controlinverter/bridge including bridge connected MOSgated devices; a controlASIC electrically coupled to the bridge connected MOSgated devices ofthe three phase MOSgate control inverter/bridge, the control ASICincluding all control circuitry required to control thestarter/alternator machine; and a motor drive circuit electricallycoupled to the control ASIC.

[0005] In accordance with an example embodiment of the presentinvention, the control ASIC is capable of operating in a variety ofmodes. These modes may include, for example, “a starter mode,” in whichthe control ASIC drives the bridge connected MOSgated devices of a threephase MOSgate control inverter/bridge 115, such that gate-to-sourcevoltages of the bridge connected MOSgated devices are held for aduration of a start-up sequence. The variety of modes may also include,for example, an “alternator mode,” in which the control ASIC drives thebridge connected MOSgated devices of the three phase MOSgate controlinverter/bridge to rectify an alternating voltage from thestarter/alternator machine.

BRIEF DESCRIPTION OF THE DRAWING

[0006]FIG. 1 is a block diagram of a starter/alternator system employinga novel control ASIC according to the present invention.

[0007]FIG. 2 is a block diagram of a novel control ASIC according to thepresent invention.

BRIEF DESCRIPTION OF THE INVENTION

[0008] Referring to the Figure, there is seen a block diagram of astarter/alternator system 100 according to the present invention.Starter/alternator system 100 is configured to start an automotivevehicle engine 205 and to charge an automobile battery 210.Starter/alternator system 100 includes a starter/alternator machine 110,a three phase MOSgate control inverter/bridge 115 electrically coupledto starter/alternator machine 110, a novel control ASIC 130 electricallycoupled to three phase MOSgate control inverter/bridge 115, and a motordrive circuit 120 electrically coupled to novel control ASIC 130. Inoperation, engine 205 is operated by the starter/alternator machine 110,which is driven, in turn, by the output of the three phase MOSgatecontrol inverter/bridge 115 in a conventional manner.

[0009] In accordance with the present invention, however, the bridgeconnected MOSgated devices (not shown) of three phase MOSgate controlinverter/bridge 115 are switched under the control of a single novelASIC 130, in which resides all control “intelligence” (i.e., controlcircuitry) required to control starter/alternator machine 110. NovelASIC 130 responds to input control signals from motor drive circuit 120,which receives feedback signals 125 a, 125 b from the output of threephase MOSgate control inverter/bridge 115 and starter/alternator machine110. Novel ASIC 130 is capable of machine winding and excitation fieldgrounding when the automobile engine is stopped and of measuring thetemperature of the substrate of novel ASIC 130. Novel ASIC 130 may alsobe provided with an additional high side driver for field transistor,and may be designed to operate in a variety of different voltagenetworks (e.g., 12V and 42V systems) in a wide operating temperaturerange (e.g., −40° C. to 165° C.).

[0010] Novel ASIC 130 is configured to operate in various operatingmodes. In accordance with one embodiment of the present invention, novelASIC 130 is configured to operate in a “starter mode,” in which novelASIC 130 drives three phase MOSgate control inverter/bridge 115, suchthat the gate-to-source voltages of the bridge connected MOSgateddevices (not shown) of three phase MOSgate control inverter/bridge 115are held for the duration of the start-up sequence. This may beaccomplished, for example, using a bootstrap and/or charge pumptechnique. The “starter mode” of operation may be initiated, forexample, by an external microprocessor. For this purpose, novel ASIC 130may be provided with a control input (e.g., input #2 in the table below)configured to receive a “starter mode” signal from the externalmicroprocessor input (when the car engine is to be cranked).Alternatively, “starter mode” may be initiated by asserting and/ordeasserting one or more other input signals (e.g., at least one inputsignal IN, . . . , IN6 in the table below). In “starter mode,” novelASIC 130 helps.

[0011] In accordance with another example embodiment of the presentinvention, novel ASIC 130 is also configured to operate in an“alternator mode,” in which novel ASIC 130 drives the gate nodes of thebridge connected MOSgated devices (not shown) of three phase MOSgatecontrol inverter/bridge 115 to rectify the alternating voltage fromstarter/alternator machine 1 10. Similar to “starter mode,” “alternatormode” may be initiated, for example, by an external microprocessor. Forthis purpose, the “starter mode” control input (e.g., input #2 in thetable below) connected to the external microprocessor may be used to“toggle” between “starter mode” and “alternator mode” (e.g., logic “0”for “starter mode,” and logic “1” for “alternator mode,” or vice versa).Alternatively, “alternator mode” may be initiated by asserting and/ordeasserting one or more other input signals (e.g., at least one inputsignal IN, . . . , IN6 in the table below). For example, in accordancewith another example embodiment of the present invention, “alternatormode” is initiated by tying to ground all input signals (e.g., IN, . . ., IN6 of #1 in the table below). In “alternator mode,” novel ASIC 130should be capable of synchronous rectification either by a Vds sensingscheme (e.g., turn on MOSFETs at Vds<Vo (typically Vo=−400 mV) and thenturnoff MOSFETs based on phase voltage measurements). Novel ASIC 130should also be capable of providing controlled avalanche (through azener from Drain to Gate) during a load dump condition.

[0012] In accordance with another example embodiment of the presentinvention, novel ASIC 130 includes an electrical pin layout as describedin the table below: I/O # Type Name Description I 1 Logic IN, . . . ,IN6 Q1, . . . , Q6 inputs I 2 Logic S/A TOGGLE Toggles between starterand alternator mode I 3 Logic WG Grounds machine windings and excitationfield I 4 Analog D1, D3, D5, Drain and source voltage for all S1/D2,S3/D4, MOSFETs. Used to turn on/off S5/D6, S2, the MOSFETs in alternatorS4, S6 mode. I 5 Power Vcc, gnd Power pins O 6 Gate signal G1, . . . ,G6 Gate voltage O 7 Gate signal S1, . . . , S6 Source voltage (thesecould be combined with signals above) O 8 Analog T Substrate temperature

[0013] Referring now to FIG. 2, there is seen a block diagram of anexemplary novel ASIC 130 according to the present invention. As shown inFIG. 2, novel ASIC 130 is coupled to the gate nodes of MOSgated devices205 a, 205 b of three phase MOSgate control inverter/bridge 115 fordriving MOSgated devices 205 a, 205 b in at least one mode, for example,a “starter mode” and an “alternator mode,” as described above. NovelASIC 130 includes a standby logic and pass circuit 210 electricallycoupled to an ALG input and Vcc; a missing ALG error detection and powersupply circuit 220 electrically coupled to Vcc and ground; a controllogic circuit 240 electrically coupled to missing ALG error detectionand power supply circuit 220; high-side and low-side voltage regulatorcircuits 215 a, 215 b electrically coupled to standby logic and passcircuit 210; high-side and low-side Vds linear control circuits 225 a,225 b electrically coupled to high-side and low-side voltage regulatorcircuits 215 a, 215 b, respectively; high-side and low-side starter modepre-driver circuits 230 a, 230 b electrically coupled to high-side andlow-side voltage regulator circuits 215 a, 215 b, respectively;high-side and low-side output driver circuits 245 a, 245 b electricallycoupled to high-side and low-side voltage regulator circuits 215 a, 215b, high-side and low-side Vds linear control circuits 225 a, 225 b, andhigh-side and low-side starter mode pre-driver circuits 230 a, 230 b,respectively; high-side and low-side low phase signal detection circuit235 a, 235 b electrically coupled to high-side and low-side voltageregulator circuits 215 a, 215 b, high-side and low-side Vds linearcontrol circuits 225 a, 225 b, high-side and low-side output drivercircuits 245 a, 245 b, and high-side and low-side starter modepre-driver circuits 230 a, 230 b, respectively; high-side and low-sideshort circuit detection circuits 250 a, 250 b electrically coupled tohigh-side and low-side output driver circuits 245 a, 245 b,respectively, and to control logic circuit 240; an over-temperaturecircuit 255 electrically coupled to control logic circuit 240;input/output stage circuits 260 a, 260 b electrically coupled to VD andSC control inputs; a lever shifting circuit 265 electrically coupled toinput/output stage circuits 260 a, 260 b and to a ground input; and anon-overlap circuit 270 electrically coupled to lever shifting circuit265 and high-side and low-side starter mode pre-driver circuits 230 a,230 b.

[0014] Although the present invention has been described in relation toparticular embodiments thereof, many other variations and modificationsand other uses will become apparent to those skilled in the art. It ispreferred, therefore, that the present invention be limited not by thespecific disclosure herein.

What is claimed is:
 1. A starter/alternator system for an engine and abattery of an automobile, comprising: a starter/alternator machine; athree phase MOSgate control inverter/bridge electrically coupled to thestarter/alternator machine, the three phase MOSgate controlinverter/bridge including bridge connected MOSgated devices; a controlASIC electrically coupled to the bridge connected MOSgated devices ofthe three phase MOSgate control inverter/bridge, the control ASICincluding all control circuitry required to control thestarter/alternator machine; and a motor drive circuit electricallycoupled to the control ASIC.
 2. The starter/alternator system of claim1, wherein the motor drive circuit includes feedback inputs electricallycoupled to respective feedback signals.
 3. The starter/alternator systemof claim 2, wherein the feedback signals include a first feedback signalgenerated by the three phase MOSgate control inverter/bridge and asecond feedback signal generated by the starter/alternator machine. 4.The starter/alternator system of claim 1, wherein the control ASIC iscapable of operating in a plurality of different voltage networks. 5.The starter/alternator system of claim 4, wherein the plurality ofdifferent voltage networks include a 12 volt voltage network and a 42volt voltage network.
 6. The starter/alternator system of claim 1,wherein the control ASIC is capable of operating in a wide operatingtemperature range.
 7. The starter/alternator system of claim 6, whereinthe temperature range is −40° C. to 165° C.
 8. The starter/alternatorsystem of claim 1, wherein the control ASIC is capable of operating in aplurality of modes.
 9. The starter/alternator system of claim 8, whereinthe plurality of modes include a starter mode, the control ASIC drivingthe bridge connected MOSgated devices of three phase MOSgate controlinverter/bridge in the starter mode, such that gate-to-source voltagesof the bridge connected MOSgated devices are held for a duration of astart-up sequence.
 10. The starter/alternator system of claim 9, whereinthe control ASIC includes at least one control input, the starter modeof the control ASIC being initiated by the assertion of the at least onecontrol input.
 11. The starter/alternator system of claim 8, wherein theplurality of modes include an alternator mode, the control ASIC drivingthe bridge connected MOSgated devices of three phase MOSgate controlinverter/bridge in the alternator mode to rectify an alternating voltagefrom the starter/alternator machine.
 12. The starter/alternator systemof claim 9, wherein the control ASIC includes at least one controlinput, the alternator mode of the control ASIC being initiated by theassertion of the at least one control input.
 13. A control ASIC for usein a starter/alternator system for an engine and a battery of anautomobile, the control ASIC comprising: an ASIC configured toelectrically coupled to bridge connected MOSgated devices of a threephase MOSgate control inverter/bridge of the starter/alternator system,the control ASIC including all control circuitry required to control astarter/alternator machine of the starter/alternator system.